Vintage Single Square Black Cut Out Cufflink

This vintage cufflink is made of a gold tone metal and has a gently pointed toggle. The face is a golden square outline with a cut-out center, and a black rectangular stone sitting in the middle. The flat side of the toggle is inscribed, "PAT 2974381" but there is no maker's mark anywhere to be found. The piece has normal vintage wear and some tone change throughout but is still wearable (and excited to find a mate). Dimensions: 19x19mm Weight: 6.88g Love the piece but not the price? Make an offer!